


Switchity Switcheroo - Which One Is Atsumu?

by neonstardust



Category: Haikyuu!!
Genre: Alternate Universe - Magic, Alternate Universe - Same School, Alternate Universe - Shapeshifters, Don't Let The Tags Fool You This Is Safe For Work, HQ Monster Lovin Weekend, HQ Monster Lovin Weekend 2020, Human/Monster Romance, Is This Platonic? Is This Romantic? The Answer Is Yes, Shapeshifter Miya Atsumu, Shapeshifter Miya Osamu, Shapeshifters - Freeform, Shapeshifting, Yachi Hitoka-centric, shape shifting
Language: English
Status: Completed
Published: 2020-11-01
Updated: 2020-11-01
Packaged: 2021-03-08 02:47:17
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,800
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26964664
Author URL: https://archiveofourown.org/users/neonstardust/pseuds/neonstardust
Summary: Having the same face as your identical twin has its perks, but when you’re a shapeshifter, you’re an unbeatable master of disguise.At least, that’s what Atsumu thought, until one Yachi Hitoka came along.
Relationships: Miya Atsumu & Yachi Hitoka, Miya Atsumu/Yachi Hitoka
Comments: 4
Kudos: 72
Collections: An Asexual's Guide to Monster Lovin Weekend: Because Maybe Hot Monsters want to be Called Beautiful Monsters Just One Time





	Switchity Switcheroo - Which One Is Atsumu?

**Author's Note:**

> HQ Monster Lovin’ Weekend - Prompt: Shapeshifting
> 
> P.S. - Props to those who understood the title reference.

“Morning, Osamu-kun!”

“Sup, Osamu-san.”

“Yo, Osamu! Can I borrow your notes for science class?”

With a tired smile, he hands over the notes, nodding to the others. “Morning.”

“Hey, Atsumu-kun.”

“I’m Osamu.”

“Oh! Sorry,” she apologizes quickly, disappearing twice as fast.

Atsumu thinks he must be a living case of irony. That or an identity crisis in human form. Ancient magic, spells, potions: he doesn’t need any of that. All he has to do is comb his hair the opposite direction, and suddenly he’s someone else. A shapeshifter’s never had it so easy before.

“Osamu-san, will you sign the petition for more art programs?”

Pulling out a pen, Atsumu signs without really looking. Just like his face, he has the same handwriting as his brother.

“Atsumu-kun, what up?”

He turns to correct them, but he stops short, finding himself face to face with the real Osamu. The surprise drips away like a drop of sweat on a hot sidewalk. “Sup, ‘Tsumu.”

Osamu catches on fast. “Hey, ‘Samu.”

Just like that, they part ways, and the charade continues. Already, Atsumu is bored with the game. No one ever sees through it, and those who come close to recognizing him back down immediately upon receiving the slightest correction. Still, it’s not like he has anything better to do with a Monday morning than impersonate someone else.

Two girls wave at him as he passes by. “Hey, Osamu-san.”

“Did you make onigiri today?” the other girl, probably someone from Osamu’s class, asks.

“Maybe next time,” he says. His voice is the only thing he needs his magic for. He’s still not sure where the genes split between them to give them two different voices, but it doesn’t matter in the end. He doubts anyone would notice if he used his own voice with his brother’s name.

“Osamu-kun? Oh.” Yachi blinks. “Sorry, Atsumu-kun. I overheard those girls and thought your brother was here.”

“I am Osamu,” he says dryly.

Yachi tilts her head. “No?”

Atsumu stops and spares her a flat look. “I think I know my own name. The jury is still out on if ‘Tsumu does or not.”

Her brow furrows. “Is this a new game, Atsumu-kun?”

He doesn’t know what to say to that. Staring blankly, he waits for her to give up and accept his lie.

Her eyes widen like she’s just had an idea, and he bites back a smile. She’s going to apologize for “mistaking” him as his brother and concede defeat.

Yachi leans close and whispers, “Are you in trouble and pretending to be Osamu-kun to get out of detention?”

“It’s ok—hah?” Atsumu takes a step back. “You’re still going on about this?” He scratches the back of his head. “I’m starting to get offended.”

“I’m sorry.” She holds her hands up, placating. “I won’t tell Osamu-kun,” she promises.

Atsumu stares. Dumbfounded, he looks himself over, but he has no giveaways. He parted his hair in Osamu’s usual style, and their uniforms match to the letter. His nondescript slippers can’t be to blame. He’s not even carrying a backpack or a phone that could signal him out. So how...

Yachi watches him innocently. “Let me know if you need any help, okay?” Winking she adds, “ _Osamu-kun_.”

Atsumu’s jaw twitches. He is not losing this easily. Letting his magic slip over him like a cloak, he holds out his arms for her to inspect him. “I don’t know what you’re looking at that makes you think I’m Atsumu, but I really am Osamu.”

He’s beaten her now. He must’ve had something small like a freckle that was giving him away, but now no human, not even their mother, can tell the difference between them. His magic will conceal anything on him that doesn’t match up perfectly against Osamu.

Yachi chews on her lip. “I’m starting to worry,” she says. “Did... Did I upset you, Atsumu-kun?”

“I’m Osamu,” he repeats.

She smiles, but this time it’s sad. “Right.” Taking a step back, she says, “I better get to class. I’m sorry if I upset you, Atsumu-kun.”

A spark of regret flares in his chest, and he grabs her hand before she can run away. “Wait.” He sighs. “Damn, you’re persistent.”

Frowning, she asks, “What’s going on?”

There are too many people in the cramped hallway, but he supposes the jig is up either way. “What gave me away?” He leads her into an empty classroom. A mirror hangs next to a poster on eye color, and he stands in front of it, turning his head from side to side. “I could’a sworn we got the same face. Did he get a new freckle?”

Standing in the middle of the room, Yachi looks from him to the exit. “What’s happening?” She covers her mouth with her hands. “Oh my stars, are you running from the police? The yakuza?”

Atsumu catches her gaze through the mirror. “No.” Turning around, he leans against a nearby desk. “Also, I’m offended.”

“Sorry.” She chuckles nervously. “I get carried away sometimes.”

“Mhm.” He looks her over slowly. Yachi has never given off any kind of vibes of being anything less than human. Excluding his brother and his mom, Atsumu has never even encountered another shapeshifter before, let alone someone with the power to see through his magic. “What are you?” he asks.

“One forty-nine centimeters,” she says without pausing. Her face turning pink, she adds, “But I’m drinking milk! My family just isn’t so... tall.” The last word comes out as a mumble, and she looks away.

Atsumu tucks this information into his memory for later. He can celebrate their height difference—over thirty centimeters—after he figures out this mystery. That doesn’t stop his heart from doing a happy skip, though.

He crosses his arms over his chest. “Does your family have magic?”

“Magic? No.” She holds her index finger to her lips for moment. “I think my cousin may have married someone who claimed to be a descendant of some type of magic wielder, if that helps. Why are we talking about this again?”

“How did you know I’m not Osamu,” he asks outright.

Now Yachi is the one staring at him as if searching for an answer. “You look nothing like him,” she says. Wincing, she continues, “Well, I mean, you do look like him, but not like, um... Gosh, I’ve never thought of how to describe it before.” She scratches her head.

“We’re identical twins,” he reminds her. It’s no secret he’s a shapeshifter either, but he leaves that part out. If she isn’t aware she can see through magic yet, he may be able to use that to his advantage.

“I know. How do I put this?” She makes a vague hand gesture. “You’re just different.” Reaching out, she points at his chest. “You have different hearts, and your personalities are nothing alike.”

That has nothing to do with their physical appearances. Maybe she was just blessed with gifted eyesight. Atsumu let’s his head thump back against the wall. What a pain.

Yachi puffs out her cheeks. “I mean it. I could never mistake you for anyone else.”

His eyes light up. “Is that a challenge?”

“Um? No?” Yachi backs away. “No, sir. No challenge here.”

Smirking, he dashes out into the hall. Most of the students have headed off to class already, but he grabs Yamaguchi by the arm, yanking him into the classroom.

Magic wraps around him. His features shift and change. Long bangs fall into his eyes. This body is smaller than he’s used to, but Atsumu adjusts quickly, scratching at his cheek just as Yachi turns to face them.

“What’s going on?” he and Yamaguchi ask at the same time.

Yamaguchi jumps. “What? Miya-san, is that you?”

Atsumu throws his hands up in mock surprise. “Miya-san, you startled me,” he lies.

Yachi claps. “That’s really good, Atsumu-kun.” She’s staring right at him, unfazed by his disguise. Turning to the real Yamaguchi, she says, “I’m sorry for the scare, Yamaguchi-kun.”

“It’s okay, I guess.” He looks between them uncertainly. “See you after class, Yachi-san.”

He doesn’t get it. Atsumu stares down at his hands, watches the freckles and scabs fade away as the transformation slips off him. Did he make a mistake? He’s sure Yachi didn’t see them enter the room. Then, how?

A soft tug on his sleeve grabs his attention. Looking up, he finds Yachi watching him, her gaze brimming with concern. “Are you okay, Atsumu-kun?”

“How did you know?” he asks. He’s never failed before, not since he was little. It’s not possible.

Yet Yachi stands before him, looking at him like it’s the most obvious thing in the world. “I could never mistake you for someone else,” she says. “You’re the one and only Miya Atsumu.”

“My father’s name was Atsumu,” he lies.

“Oh, I’m sorry.”

“I’m kiddin—”

“I meant in here.” She places her hand over his heart. “Not your name—your soul. It’s one of a kind.” Smiling, she says, “That’s why you’re too special to mistake for anyone else.”

Atsumu’s lips part, but for the first time ever, he has nothing to say. He can feel his heart beating overtime. She must be able to feel it, too, and that only makes him feel weirder. He wonders if this is what it’s like to be nervous. His chest feels warm and fluttery. He can’t decide if he likes this or hates it.

“Oh, we’re going to be late,” Yachi warns. Dropping her hand from his chest, she grabs his wrist and pulls. “Let’s hurry!”

Hearing that just makes him want to drag his feet, but he humors her, letting her pull him out into the hall. “You sure you’re not magic?” he asks.

“Mhm hmm.” Reaching her classroom, Yachi let’s go of his wrist. “I’ll see you after school,” she says.

Warmth lingers on his skin, and he puts his hand where hers was so he can hang on to that feeling. “I’ll see you at lunch,” he corrects. Magic or not, he likes whatever this is.

She smiles. “I’ll save you a seat.”

The bell rings.

“Eek! Go! Shoo!” She pushes him towards his class.

Atsumu lingers. This close to her, he can truly appreciate their height difference, and he wonders what it would be like to hold her hand properly. There’s no time for that now, but that’s fine. Atsumu has never had a problem with taking his time, and he has an entire school year to unravel the mystery that is Yachi Hitoka.

Pulling her into a quick hug, he finally starts walking to his class, but not without stopping to memorize the bright blush burning across her cheeks first. Atsumu grins. Maybe there are better ways to spend his Mondays than impersonating people after all.


End file.
